Process of removing surface finish



UNITED STATES DAVID P. CLEVELAND, 01 DALLAS, TEXAS,

PATENT OFFICE.

AS SIGNOB T0 UNIVERSAL PAINT REMOVED AND MOTOR CLEANING COMPANY, 01 DALLAS, TEXAS, A GOKHON LAW COMPANY HAVING AS ITS TRUSTEES ED WILKEBSON, J. A. BERGFELD,

AND DAVID P. CLEVE- Patented Oct. 5, 1920.

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rnoonss or ammovmo summon rm'rsn.

1,355,074, Specification of Letters ram. Io Drawing. Application med December 30, 1919. Serial R0. 348,472.

T o allwhom it may concems Be it known that I, DAVID P. CLEvELAND, citizen of the United States of America, re-

siding at Dallas, in the county of Dallas and State of -Texas,

' automobiles, furniture, walls, floors, or other coated objects, which it is desired to repaint or refinish, and the rocess is especially useful in connection with the removal of paint and varnish from automobiles.

Various compositions under the name paint or varnish remover have heretofore been employed for this purpose, many of which contain an alkali, these com ositions being usually applied with a brus or mop, and after being allowed to stand, the coating may be scraped off with a putty knife, or some similar tool. Another recognized method is by immersing the article in the paint-remover liquid, for a desired period. In accordance with the present invention, the preferred mode is to apply aspray of an alkali solution, this being sprayed or atomized onto the sur ace under treatment, by means of a jet of steam, and the liquid being thereby applied to the surface at approximately a boiling temperature. The preferred mode is to use a relatively large amount of steam, and a relatively small amount of the alkali solution, the lat ter being conveniently supplied to the nozzle or sprayer by gravity as from an elevated tank, or in other words the solution reaches the nozzle under some hydrostatic pressure. In this modeof operation wet steam is entirely suitable, and this acts not only to heat and atomize or s ray the solution, but also such an excess 0 steam is used that it heats the surface of the article being treated to about the boilin point of the liquid. This method, especial y when usin the. particular solution or mixture referred surfaces.

referably v to below, completely loosens the coating, so that it can-readily be washed off.

It is preferable to apply steam with the mist of liquid particles, in such an amount as will not only thoroughly heat the work and the paint remover liquid, but also to furnish, by condensation, water in amount capable of washin off a large part, or even all of the loosene pigment of the paint.

iaints and varnishes, when the same have dried on the surfaces of painted articles, consist largely of oxidized and dried oils, resins, gums, etc., together with insoluble pigments and the like. The action of the hot alkali on such a product is to saponify the organic material. This is, when saponified, in solution in the water contained in the paint remover li uid and the further amounts of water pro ucedby condensation of steam, tend to quite thoroughly wash off the soapy solution and loosened pigment, together with whatever dirt, dust, etc, may also be present. This action is especially useful as applied to vertical or other non-horizontal A mode of operation is this first to apply the remover liquid by atomization, while supplying a considerable excess of wec'steam and supplying the liquid to the atomizer under some pressure, e. 9.,

by, gravity. The workman holds the atomizer in his halid, and moves the same horizontalllg hack and forth, across the 11 per part agiven area of the surface. his operation is continued, gradually working downwardly overz'fthe surface under treatment, until a -derable amount of surface has been leaned. This operation is tinned, on, portion of surface, until 1; e paint 'sh are thoroughly removed. 7

During this treatment, the alkali solution ainted'surface adjacent to such trimmings, 10!

y any ordinary paint-removing methods.

When the paint and varnish have been loosened and substantially all removed from the surface orfrom some art thereof (say the back of an automobile it is advisable, but not necessary, to shut off the flow of paint-remover liquid to the atomizer, and to then go over the entire surface (which may have cooled more or less in the mean time) with a steam jet, to wash off adhering particles of pigment, flakes of loosened paint, and particularly the adhering film of dried paint remover. Or the entire job may be finally washed with a stream of hot or cold water from a hose, nozzle or atomizer.

In some instances it is advisable to apply to the surface from which thepaint has een removed, a material havin an acid reaction (acetic acid being suitable for the purpose of completely neutralizing any residue 0 alkali. This step is optional, and if used will, of course, be followed by a washing with water.

This leaves the original surface, practically as it stood before the original painting. It is usually unnecessary to sandpaper the work before repainting, although a light rubbing with steel wool or fine sand-paper mag be advisable in some cases.

fter thoroughly drying the surface, the work is then ready for repainting, reenamelin or other like operations.

t has been found that surfaces from which the paint has been removed by this process, will more readily take a new coating of int.

he paint-remover solution preferably used is a dilute solution of a fixed caustic alkali. It is advisable to also have present in the solution a quantit of an alkaline earth hydrate, such as by rated lime.

The solution can be varied considerably and a convenient and eilicient solution for removing paint from automobiles (the original painted surface being metal) is one made by adding 10 pounds of caustic soda and one and one-quarter pounds of lime, to 2-5 galions of water. The lime precipitates any carbonate originally present in the caustic soda and a small amount of dissolved lime in the solution seems to be helpful. Caustic potash could also be used, as a substitute for all or a part of the caustic soda. The mixture is preferably made up, stirred well and settled, after which it may be drawn ofl from the sediment or precipitate. The proportions and strength can be varied to a considerable extent. .Of course, solutions of such a strength that they would injure the metal or wood or other material from which the paint is being removed, should not be used. 7

The above described solution is merely one of the eflicient and suitable mixtures whichhave been found to give good results in the process, and the invention is not limited thereto. Any solution of fixed caustic alkalis of suitable degree of concentration can be employed.

The process is one which lends itself readily to the treatment of vertical or non-horizontal surfaces, the liquid reaction products flowing away from the finished work by gravity.

By the use of this invention it is ossible to c can the surfaces in a remarkabfj short time, and with a minimum amount of hand labor. It has been repeatedly demonstrated that all the paint from a 7-passenger automobile can be removed by this process, in less than an hour. This includes removal of the paint from the fenders and hood, as well as from the body.

The present application is in part a continuation of m 1,prior application Serial No. 300,583, file ay29, 1919.

What I claim is:

1. In the removal of finish coating, the step of maintaining the surface portions of the work undergoing treatment, at a temperature not substantially below the boilin point of water, by directing against suc surface, by the agency of a hot vapor-form fluid, a spray jet of finish remover comprising a solution of a fixed alkali, such jet containing steam.

2. In the removal of finish coating, the step of maintaining the surface portions of the work undergoing treatment, at a temperature not substantially below the boilin point of water, by directing against suc surface, by the agency of a hot vapor-form fluid, a spray of finish-remover comprising a solution of a fixed alkali, such jet containing steam; and simultaneously supplying hot li uid to the point of apiglication of the finis -remover in amount su cient to completely remove the products of the reaction of the alkali with ingredients of the finish.

3. A process from an article,

of removing finish coating which comprises the step of simultaneously applying steam and a jet finish-remover containing a dilute soultion of a fixed caustic alkali, to the surface of said article, the amount of steam being sulficient to maintain the caustic solution on the surface in subst ntially a boiling condition until the finish 1S disintegrated.

4. A process of removing finish coating from an article, which comprises the step of spraying by the agency of a jet of steam, onto the surfaceof said article, a dilute solution in water containing a fixed caustic alkali, the amount of steam being suflici'ent to maintain the caustic solution on the surface in substantially a boiling condition until the finish is disintegrated.

5. The improvement in the art of removing paint and varnish which comprises atomizing against a non-horizontal surface by l means of a jet of wet steam, a dilute aqueous solution containing as an ingredient a fixed caustic alkali, the amount of steam being suflicient to maintain the solution and the surface of the work at" a temperature approximating the boiling int of water, whereby the li uefied pro nets of reaction can flow from t e surface by gravity.

6. A process of removing finish coating from an article, which com rises loosening the coating by forcibly directing against the surface of such article a hot elastic fluid comprising steam and a spray of dilute hot solution comprising an alkali metal hydroxid and water, the volume of steam be-, in many times larger than the volume of so ution and bein sufii'ciently la tain the surface 0t durin th treatment, and to loosen and wash 0 at least a large part of the finish coating.

7 A process of removing finish coating from an automobile havin non-horizonta painted and varnished meta surfaces,- which comprises spraying upon such surfaces by the agency of a relativel large volume of steam, a et of paint an varnish remover containing a fixed caustic alkali, while moving the jet over the said surfaces, a part of the excess of steam condensing to form water on the surfaces to aid in flowing oil the disintegrated paint and varnish material, and reaction products.

8. The process of removing finish coatin from an article which comprises the step 0 directing upon the surface of said artic e a jet comprising steam and an aqueous solution of a fixe caustic alkali at such a high temperature and in such volume as to effect disintegration and removal of at least the major part of the finish coating.

9. A process of removing finish coatin from an article which comprises the step 0 atomizing b the agency of a jet of steam, onto the sur ace of said article, a dilute solution in water containing a fixed caustic alkali, such solution being applied to the surge to mainfrom articles,

face hot and being of sufficient strength to disintegrate the finish coating.

10. process of removing finish coatin from an article, which comprises the step 0% spraying by a jet of a hot elastic fluid inc uding steam, onto a hot surface of said article, a dilute solution comprising a caustic alkali in water, said solution being of suflicient strength and in suflicient amount to disintegrate said finish coating and to remove at least the greater part thereof.

11. A rocess of removin finish coatin from articles, which comprises the step 0 spraying by the agency of a jet of steam, onto the surface of said articles a dilute solution in water containing a fixed caustic alkali.

12. The improvement in the art of removing paint and varnish which comprises spraying a ainst a non-horizontal surface by means 0 a jet of steam, a dilute aqueous solution containing as an ingredient a fixed caustic alkali.

13. A rocess of remov' finish coatin from articles, which com rises the step 0 spraying, by the agency 0 a jet of hot elastic fluid onto the surface of said articles, a dilute solution comprising an alkali metal hydroxid and a somewhat soluble alkaline earth metal hydroxid, in water.

14. A process of removing finish coating which comprises loosening the coating by spraying upon the same by the agency of a hot elastic fluid, a dilute hot solution comprisi an alkali metal hydroxid, milk of lime, an

loosened coating.

15. A process of removing finish coating which com rises causing a jet of steam and a jet of alka ine paint remover liquid to mix, and directing t e mixed jet against the surface of the work, the amount of steam bein sufiicient to maintain the surface of the wor at about the boiling point of water. In testimonwhereof I aflix m si AVID P. OLE

ature. ND.

water, and washing ofi the 

